The present invention relates to a valve stem seal assembly, and in particular to a seal for a valve stem seal assembly found in overhead valve internal combustion engines.
Those skilled in the art will appreciate the manner in which intake and exhaust valves are employed in cylinder heads of internal combustion engines. In conventional overhead valve internal combustion engines, a pair of valves reciprocates in timed alternation to provide intermittent communication between the intake and exhaust manifolds and a combustion chamber. As is well known, the intake port of a combustion chamber is opened and closed by the reciprocating motion of at least one intake valve. The intake valve permits fuel mixed with air to flow into the combustion chamber. In addition, an internal combustion engine has at least one exhaust valve and associated exhaust port for releasing expended combustion gases into the atmosphere. Lubrication is provided to the upper portions of the valves. Because temperatures in the combustion chamber may approach or exceed 1000 degrees Centigrade, any lubricating oil exposed to these temperatures will vaporize or burn leaving behind deposits that may interfere with the proper sealing of the valves and cause rapid deterioration. Valve stem seal assemblies are used to seal against leakage of oil between each valve guide and its associated valve stem.
It is therefore necessary to provide seals around the upper region of the valve stems and along the valve guide down to the manifolds and combustion chamber. A typical valve stem seal takes the form of a cylinder partially closed at one end by the valve seal. The cylindrical region seats about the valve guide to maintain the valve seal stationary. An upper region of the valve stem is surrounded by the valve seal when the valve stem is fully inserted into the valve seal assembly.
Conventional valve seal assemblies comprise individual body and seal components that typically must be assembled into the valve seal assembly. In addition, the valve seal assembly, valve spring and spring retainer must be assembled individually by the end user. Further, the manufacturer must keep an inventory of the valve seal assembly, valve spring and spring retainer. The inventory of such multiple components and associated assembly increases the cost of the assembled valve seal assembly.
The inventor of the present invention has recognized these and other problems associated with valve stem seal assemblies. To this end, the inventor has developed a dual spring valve stem seal module comprising a valve spring having first and second ends, a valve stem seal retainer including a first raised edge and an annular flange for supporting said first end of said valve spring, a spring retainer having a second raised edge and retaining the second end of said valve spring and a retention spring captured by the first and second raised edges to form the valve stem seal module. The retention spring incorporates the valve stem seal assembly, the valve spring and the spring retainer to form the dual spring valve stem seal module.